Method of making a diaphragm



Dec. 14, 1954 F. A. SENGER ETAL METHOD OF MAKING A DIAPHRAGM OrigirialFiled Dec. 25, 1948 BY y - A TTORA EY:

, oval conformation. necessary, in order that the pessary'functionproperly in 'pressing against the vaginal walls,'to have a--res1l1entmetallic member or members embedded in the circular This inventionrelates to occlusive vaginal diaphragms 'or' pessaries and particularlyto a-diaph'ragm' or pessary having a rim portion without a metallicassembly therein functioning as'resilient'means and totheme'thod andapparatus for making them.

Heretofore it has been the practice ro-manufacture occlusive diaphragmsor pessaries of high grade natural rubber such as pale crepe.- Suchpessaries have been "composed of a dome-shaped thin rubber element whichis sealed or vulcanized to a continuous rim 'in'circu'lar or In such anassembly, 6 it has been edge or rim. The resilient member most commonlyused has been a single coiled spring although ln-some instances 'twocoiled springs have been used. I The manufacture of such pessarieshaving resilien'tmembers embedded in-the rim or edge has been expensive,and, consequently, such pessaries are not customarily disposed of aftera single use butareused "repeatedly over-'extended -periods of time. Anumber of diificulties'have 'been encountered in the manufacture of suchpessaries by a molding process, for'it is necessary to overcome theundesirable anddisad- 'vantageous feature which commonly'prevails whichconsists of the resilient member not being completely coated withrubber. 'This has been -overcome by'rnanually applyinglatex-to--that-portion-of *the rim at whichthe metallic resilient memberis exposed. The latex dip process has been used-to-manufacturepessaries, but it is 7 time consumingandexpensiveand requires suchcareful control of its numerous-steps that it results in many "defectivepessaries.

Among the objects of the present invention is the provision of a new andimproved pessary which is fabricated of a material other than rubber andpreferably of a synthetic thermoplastic substance.

Another object of the invention is the provision of a new and improvedmethod for manufacturing a pessary from a synthetic thermoplasticsubstance.

Still another object of the invention is the provision of a new andimproved pessary of a synthetic thermoplastic substance in which theresilient means, by which the pessary closely conforms to and contactsthe vaginal walls, is a synthetic thermoplastic substance.

Another and further object of the invention is the provision of apessary which is sufficiently low in cost of construction and materialsto be economically disposed of after a single use.

Another object of this invention is the provision of a new and improvedmolded article having a dome-like shape and a resilient rim or edgewithout the inclusion of metal resilient means.

With these and other objects in view, the invention as hereinafter morefully set forth and pointed out in the claims may be illustrated in theaccompanying drawing in which:

Fig. 1 is a perspective view of the pessary;

Fig. 2 is a view in elevation of the pessary;

Fig. 3 is a vertical cross-sectional view of the pessary;

Fig. 4 is an enlarged fragmentary view in cross-section showing thediaphragm ring in one modification;

Fig. 5 is an enlarged fragmentary view in cross-section showing amodification of the diaphragm;

Fig. 6 is a cross-sectional view of the elements of a mold, shown spacedapart, used in manufacturing diaphragms;

United States PatenfO 2,697,057 Patented Dec. 14, 1954 *Fig; 7 is a viewsimi1ar tothat of Fig; 6 but showing --F-ig." 8 is" a view-similarto'F-igsl 6 and 7 but showing 'the mold elementsin closed position andfilled with a thermoplastic "composition; and

Fig? 9-iis an-enlarged fragmentary view ofFig. 8 show- "ing the relationof the membrane tothe rim of the diaphragm'and the manner in which-it-is sealedto the rim "Whenthe mold is closed.

Referringparticularly-now to Figs. 1 and 2, there is *shown a pessary 10-including=a membrane '11 of a syn- -"-thetic,--nontoxic, flexible,impermeable, thermoplastic "substarice' and' a-rnar ginal rim portion#12. "The rim portion-12 maybeof any desired shape such as that of acircle or an ellipse.

The rimtportion 12 maybe composed of the same material as that of whichmembrane 1'1 is'co'mp'o'sed or rimtportion 12 maybe composedof adifferent synthetic, thermoplastic, non-toxic, flexible, im-'permeable'substance; butvinlall instances it is necessary that-membrane11 he capable of being heat sealed to -ma'rginal rim portion 12. Asspecifically'illustrated in Fig.-5',-'therim portion in the preferredembodiment is in the nature of acontinuous hollow tube, but itis'contemplated that it'may be in the form ofasolid continuous rod, asillustrated in Fig. 4. The rim portion 12 may be made'from an extrudedtube or rod, which has been cut into suitable lengthsyby juxtaposingtheends thereof and "locally applying'heat sufiicient to fuse the endstogether.

Dome-shaped membrane 11'is separately formed and then heat sealed at itsedges toithe marginal rim portion 12. The dome-shaped membraneIbisapreferably of a thickness of from one to four thousandths-of aninch.

Any synthet ic thermoplastic-substance may .be used WhICh IS non-rigid,non-toxic, non-irritating, and capable The preferred synbe used whichhas an average molecular weight of from 15,000 -to 22,000. -Othernon-rigid thermoplasticsubstances, solid at room temperature, which maybe used in fabricating the pessary or diaphragm include: plasticizedpoylvinyl chloride such as that which is plasticized with tricresylphosphate or dibutyl phthalate; copolymers of vinyl chloride withvinylidene chloride, vinyl acetate, or ethyl maleate; and a blend ofpolyvinyl chloride with a copolymer of butadiene and acrylonitrile.

The process or method by which the pessary is manufactured and suitableequipment used in the manufacture thereof are illustrated in Figs. 6, 7,and 8 which show a mold having bottom and top members which when in aclosed position have a clearance not greater than five thousandths of aninch. Bottom member 20 of the mold, as shown in these figures, has acentral recessed or open portion 21 and an annular groove or recess 22.Top member 24 of the mold has a central dome portion 25 and an annularheating element 26 having an annular groove or recess 27 encircled by asearing element 28. A spring biased ring 29 (the spring is not shown)which acts as a pressure clamp is positioned in an annular recess in topmember 24 of the mold.

In the manufacture of a pessary according to the preferred method ofthis invention, the first step is the formation of the rim portions andthis is done by sealing together the two ends of a piece ofthermoplastic synthetic material in the form of tubing of proper lengthby placing the side ends in touching relation when they are at a heatsealing temperature, which is near 112 C. when polythene is used, forpolythene having an average molecular weight within the range of from15,000 to 38,000 has a melting point of approximately 112 C. The formedrim 12 is then placed in the annular groove 22 of the bottom portion ofthe mold. The formed rim should be of such a size as to fit snugly intothe annular groove. A sheet of synthetic thermoplastic substance 11having a thickness of from one to four thousandths of an inch is thenplaced over the recessed portion of the bottom member of the mold, whichbottom member is maintained at the temperature at which thethermoplastic substance being used is softened but below its meltingtemperature. The top member of the mold isalso maintained at atemperature at which the thermoplastic substance is softened but justbelow its melting temperature, and to shape the dome portion of thepessary the top member is slowly lowered whereby the dome-shaped portionof the top member of the mold comes in contact with the syntheticthermoplastic sheeting 11; and because of the temperature at which it ismaintained, it causes the sheeting to conform to its dome-like shape.Before the dome portion of the top member of the mold comes in contactwith the sheeting, the spring biased ring, which is at a comparativelylower temperature than the top or bottom mold elements, comes in contactwith the sheeting and firmly holds it in place. At approximately thesame time at which the annular groove around the dome portion of the topmember of the mold comes in contact with the rim portion of the pessary,the searing element, which is maintained at the melting temperature ofthe thermoplastic substance, comes in contact with the sheeting and cutsthe said sheeting in a circular form by melting it at the point withwhich it comes in contact with the searing element. The surface of theannular groove 27 around the dome portion of the top member of the moldis maintained at a temperature near the melting point of thethermoplastic substance and acts as a heat sealing element to seal thesheeting to the preformed diaphragm ring. The sheeting is sealed to theinner surface of the diaphragm ring, as illustrated in Figs. 3, 4, and5.

In the closed position there is a clearance between the top and bottommold members, the dome and recessed portions, of from about one to fourthousandths of an inch, in the preferred form. The top portion of themold is allowed to remain in its lowered position and in contact withthe sheeting only during the time it is lowered into the recessedportion of the bottom element of the mold and momentarily after it hasreached its lowermost position. The fusing or sealing of the membrane tothe rim portion of the diaphragm is accomplished practicallyinstantaneously on contact, and immediately after such contact the topmember of the mold is raised. The formed diaphragm is then immersed in acooling bath which causes the dome-shaped portion of the diaphragm toset in the shape of the mold.

Some changes may be made in the details of procedure 4 involved in thepractice of the method of this invention and m the constructlon andparts of the apparatus used in carrying out the method and of thesynthetic thermoplastic materials used in the fabrication of the pessarywithout departing from the spirit and scope of the invention; it is theintention of the inventors to include within the scope of the inventionany variant modes of procedure and any modified forms of structure oruse of mechanical equivalents and any synthetic thermoplastic materialswhich may be reasonably included within the scope of the invention asembodied in the following claims.

This application is a division of our U. S. application, Serial No.66,912, filed December 23, 1948, now abandoned.

We claim:

1. The method of making a diaphragm which comprises positioning a sheetof flexible, impermeable, synthetic' thermoplastic substance on one sideof a circular rim of synthetic, resilient, thermoplastic substance,having a diameter less than the sheet, so that the sheet issubstantially flat, in touching relation to the rim, and extends beyondthe outer circumference of the rim; firmly holding in place the portionof the sheet extending beyond the outer circumference of the rim,deforming the sheet at an elevated temperature into a dome, heat sealingthe sheet to the rim, the dome being positioned at the innercircumference and beyond the rim on the side opposite the seal of thesheet to the rim, and removing the portion of the sheet then extendingbeyond the outer circumference of the rim, whereby a diaphragm is madewith a continuous rim integral with a flexible domeshaped membrane.

2. A process according to claim 1 in which the substance of the rim andsheet is polymerized ethylene having an average molecular weight withinthe range of 15,000 to 22,000.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 892,702 Wyman July 7, 1908 893,739 Latham July 21, 19081,308,330 Brown July 1, 1919 1,388,123 Roberts Aug. 16, 1921 1,856,694De Correvont May 3, 1932 2,111,313 Clark Mar. 15, 1938 2,210,509 StrauchAug. 6, 1940 2,378,642 Kopplin June 19, 1945 2,402,943 Bogoslowsky July2, 1946

1. THE METHOD OF MAKING A DIAPHRAGM WHICH COMPRISES POSITIONING A SHEETOF FLEXIBLE, IMPERMEABLE, SYNTHETIC THERMOPLASTIC SUBSTANCE ON ONE SIDEOF A CIRCULAR RIM OF SYNTHETIC, RESILIENT, THERMOPLASTIC SUBSTANCE,HAVING A DIAMETER LESS THAN THE SHEET, SO THAT THE SHEET ISSUBSTANTIALLY FLAT, IN TOUCHING RELATION TO THE RIM, AND EXTENDS BEYONDTHE OUTER CIRCUMFERENCE OF THE RIM, AND HOLDING IN PLACE THE PORTION OFTHE SHEET EXTENDING BEYOND THE OUTER CIRCUMFERENCE OF THE RIM, DEFORMINGTHE SHEET AT AN ELEVATED TEMPERATURE INTO A DOME, HEAT SEALING THE SHEETTO THE RIM, THE DOME BEING POSITIONED AT THE INNER CIRCUMFERENCE ANDBEYOND THE RIM ON THE SIDE OPPOSITE THE SEAL OF THE SHEET TO THE RIM,AND REMOVING THE PORTION OF THE SHEET THEN EXTENDING BEYOND THE OUTERCIRCUMFERENCE OF THE RIM, WHEREBY A DIAPHRAGM IS MADE WITH A CONTINUOUSRIM INTEGRAL WITH A FLEXIBLE DOMESHAPED MEMBRANE.